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                SPOJ 11414. Color over a tree                </h1>
                <p>时间限制：10s&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  空间限制：128MB</p>			</div>
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                                <h3>题目描述</h3><p><p><span style="font-size: medium"><br />
Seter和Fotile在一棵N个点的树上玩游戏。这棵树的每个点不是黑色的就是白色的。</span></p>
<p><span style="font-size: medium">他们轮流进行以下操作：</span></p>
<p><span style="font-size: medium">在当前的树上选择一个白色节点；<br />
把1号点到选择节点的路径上所有点涂黑。</span></p>
<p><span style="font-size: medium">Seter或Fotile输掉游戏当且仅当无法操作（没有白色节点）。</span></p>
<p><span style="font-size: medium">Seter用石头剪刀布获得了先手机会，但是他知道Fotile很聪明，会按照最优策略选点，他想知道自己有没有可能赢得游戏，否则他就要掀桌了。</span></p>
<p></p></p><hr/><h3>输入格式</h3><p><p><span style="font-size: medium">第一行包含一个正整数N表示树的节点数。 1&lt;=n&lt;=100000</span></p>
<p><span style="font-size: medium">第二行包括N个0或1：c1,c2,..cn。<br />
ci=0 表示第i个点一开始是白色的而 ci=1 表示黑色。</span></p>
<p><span style="font-size: medium">接下来N-1行每行两个整数u,v描述整棵树。</span></p>
<p></p></p><hr/><h3>输出格式</h3><p><p><span style="font-size: medium">如果Seter输定了或者你也不会做，输出-1让他掀桌.</span></p>
<p><span style="font-size: medium">否则按照增序输出所有Seter第一步可以选择的点，使得Seter能获胜。</span></p>
<p></p></p><hr/><h3>样例输入</h3><pre>Input#1:
8
1 1 0 1 0 0 1 0
1 2
1 3
2 6
3 4
3 5
5 7
7 8 
Input#2:
20
1 1 1 0 1 1 1 0 1 0 0 0 1 0 1 0 0 0 0 0
1 2
2 3
2 4
1 5
1 6
5 7
5 8
2 9
8 10
1 11
1 12
9 13
6 14
14 15
7 16
11 17
2 18
7 19
12 20 

</pre><hr/><h3>样例输出</h3><pre>Output#1:
5

Output#2
8
11
12 

</pre><hr/><h3>提示</h3><p>没有写明提示</p><hr/><h3>题目来源</h3><p>没有写明来源</p>
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